Currently, the Cs adsorbing materials mainly include AMP-PAN resins, CuFeCN-type resins and natural minerals. These materials feature slow adsorption, long balancing time and low adsorption efficiency. Further, inspection of adsorption rate is required when used in the environmental monitoring. It takes about 10 h to process one sample. The volume of water sample for adsorption and treatment is at the level of several tens of liters.
As the research materials for concentrated adsorption of Cs in nuclear wastewater, AMP, CuFeCN, zeolite, kaolin, diatomite and iron ore are used. These materials feature lengthy processes and small adsorption capacity. The adsorption rate is 40˜95%. Therefore, the existing materials for adsorbing Cs suffer from such problems as low adsorption rate and small adsorption flow. Most of the materials have an adsorption rate of below 95% with long adsorption time and small velocity. The balanced adsorption takes several tens of hours. Therefore, these materials are not suitable for swift and highly efficient adsorption.
For instance, after the Fukushima nuclear accident on Mar. 11, 2011, U.S. WHOI investigated the radioactive impact of the Fukushima nuclear accident on the international cooperation voyages in mid-July 2011. K. Buesseler adopted AMP-PAN resin with an adsorption rate of 95% and the seawater sample velocity of about 35 ml/min. It took about 600 minutes to treat 20 L seawater sample. Although adsorption pillar realized vessel operation, it consumed a huge amount of time. Further, the adsorption rate of the adsorption pillar needed to be confirmed by ICP-MS measurement of the residual and stable Cs in the seawater past through the adsorption pillar, thereby making an accurate calculation of radioactive Cs in the seawater sample.
According to the existing marine radioactive measurement technologies owned by International Atomic Energy Agency (IAEA), it requires collecting a huge amount of seawater sample and transporting to the land base laboratory for analysis and measurement.
In summary, the existing materials for adsorbing Cs suffer from low speed and efficiency.